Count only unique failures

[camd]

This updates the counts in both Push Health, and the status lines in Treeherder for a push.

[codecov-commenter]

Codecov Report

:x: Patch coverage is 34.28571% with 23 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 79.93%. Comparing base (5d64caf) to head (fa17564).

Files with missing lines	Patch %	Lines
ui/push-health/ClassificationGroup.jsx	27.27%	8 Missing :warning:
ui/push-health/Test.jsx	20.00%	8 Missing :warning:
ui/push-health/PlatformConfig.jsx	20.00%	4 Missing :warning:
treeherder/webapp/api/push.py	33.33%	2 Missing :warning:
ui/push-health/Health.jsx	80.00%	1 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9104      +/-   ##
==========================================
- Coverage   79.95%   79.93%   -0.02%     
==========================================
  Files         600      600              
  Lines       32560    32575      +15     
  Branches     3310     3361      +51     
==========================================
+ Hits        26032    26038       +6     
- Misses       6362     6371       +9     
  Partials      166      166              

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